Busted plastic impeller in the water pump. Never did expect that.
Followed the information overload on the forums about the plastic or metal variants. Decided on the metal due to the above breakage. But there are both sides, mostly quality issues of German vs. Chinese. I bit the bullet and went with a metal impeller water pump from .. (aghast) Autozone: they had it in stock for (you kidding me?) $150, with lifetime warranty. Figured I can just pull every couple years and check if necessary.
The quality looks great in the following picture, but there are casting issues.
Detail around the metal impeller and the casting; look good.
But the casting in the German original part is much finer. Probably 10x more expensive casting mold. The pictures may not due justice, but the casting finesse around the impeller cutout in the German part is exquisite.
This image shows a casting fault in the Autozone pump within the water passage. The black silhouette inside the passage is metal that I used a dremel on to remove to smooth out. Still, I was very glad for the metal product as shown below.
Another note as well regarding the gasket. The Autozone pump came with a paper gasket. I purchased the correct metal gasket from the Porsche dealer with the embossed detent that will compress correctly. Also, the correct torque is quite minimal, so be sure to use a 1/4" torque wrench to hit correctly to prevent leaking.
After replacing, I debated if I should flush; during the week waiting for Saturday to install the new pump, I purchased the Airlift vacuum coolant system, and figured flushing will give a bit of experience, and if there is a leak, save me the $120 on the Pentafrost SF coolant. Very glad I did flush : critical step.
The black specks are all the plastic impeller remains flushed out with 4 1/2 gallons of distilled water. When I first drained the remaining the coolant during the repair, more remains flowed out. After this I was extremely glad I flushed and I got the metal impeller pump; I think it is the correct way to go.
Airlift - great tool! Checked the tightness of the new installation per instructions: Get the vacuum up to 25 psi, and check it does not go down. The instructions stated the hoses 'may collapse'. Very True! The picture is the main water hoses collapsed.
Finally, it is just incredible to me to see a car so clean with 140k+ miles. This is the coolant pipes running under the car, behind the plastic underguards. Yes, there is a shield protecting the underbelly, but still, 13 years old, a lot of miles, daily driver. Super clean! Not to mention working on a car for 12 hours without a scraped or bleeding knuckle.
Points :
Metal impeller, flush, proper gasket, Airlift.
For better or worse :
I actually enjoy working on this girl. Sigh.